Re: [perfmon2] [PATCH] perf_events: add PERF_SAMPLE_BRANCH_STACK

[Peter Z. <pe...@in...>]

On Wed, 2010-04-07 at 14:45 +0200, Stephane Eranian wrote:
>         LBR is configured by default to record ALL taken branches.  On some
>         processors, it is possible to filter the type of branches. This will
>         be supported in a subsequent patch.
> 
>         On other processors, the sample type is allowed but will generate a
>         sample where nr=0 as is the case with other sampling types.

Right, so I already posted a patch like that:
  http://lkml.org/lkml/2010/3/4/160

and the reason its not merged is because there is no perf use-case for
it. Ingo wants to avoid merging ABI bits for which there is no userspace
around. We already have a few such things and we find that its too easy
to regress on those part.

So if you want this, please also implement a useful use-case in perf.